In 2007, the U.S. Fish and Wildlife Service removed grizzly bears, also known as brown bears, from the endangered species list, but a federal appeals court has this week overturned this decision.

The judges stated that wildlife managers had made a mistake in denying the animals protection under the Endangered Species Act, which had, along with a recovery strategy, been responsible for a three-fold increase in the number of grizzlies in the greater Yellowstone region over the last 35 years.

The court cited climate change as the reason behind the ruling, with warmer weather contributing to the unprecedented die-off of the whitebark pine, a key food source for the grizzly bear. Along with the polar bear, the grizzly bear is now one of just two species to have earned protection as a result of the effects of global warming.

Whitebark pine trees are a source of food for grizzly bears

Deadly beetle

The effects of climate change have enabled the larvae of the pine beetle, a major pest, to avoid the typical seasonal die-off and thrive. In recent years, pine beetles have survived the warmer winters, leaving them to destroy an estimated 16% of whitebark pine trees, and damage a further 25%.

Diana Tomback, a whitebark pine expert at the University of Colorado, Denver, explains that the intensity and scale of the infestation and destruction is unprecedented, “Studies show that the majority of watersheds in the greater Yellowstone ecosystem have been ravaged and there are lots of places where there is 90%-plus mortality of beetle-ravaged mature trees.”

The pine beetles bore under the tree bark, and create internal canals which eventually play host to thousands of beetle larvae. This intense damage stresses the pines, which turn a vivid red.

The grizzly bear is once again protected by federal law

Avoiding potential conflict

Record numbers of grizzlies have been euthanised by park and wildlife officials in recent years, as a result of the animals being responsible for the deaths of several tourists and hikers. In 2010, approximately 75 grizzly bears were either killed or removed from the wild.

The panel of judges in the appeal court took into serious consideration the warning from conservationists that the loss of trees in the upper reaches of Yellowstone National Park and its surrounds would probably drive the grizzlies to more populous areas to forage. This change in habitat use by the bears will potentially increase the frequency of confrontations between the omnivorous mammals and humans and their livestock.

Andrew Wetzler, an attorney for the Natural Resources Defense Council, states that the whitebark pine may eventually be joining the grizzly bear as a protected species: “Since delisting, the Fish and Wildlife Service has said itself that white-bark pine should be listed independently as an endangered species.”